PubMed1989
The etiology and pathogenesis of PBS are still quite vague, despite very intensive investigations performed in that field. Numerous data can be found in the literature that contribute to the knowledge of PBS and to the explanation of this condition. Taking into consideration the data available (case descriptions, embryology, experimental embryology, genetics), PBS is meant to occur due to the disturbance of inductive interaction of tissues which leads to a deficient cell differentiation and to the disturbances of the primary field, resulting in multiple malformations which developmentally belong to the primary field in question. The causes inducing deficient tissue differentiation and the impediments disturbing inductive interaction are numerous and various. According to data in the literature, disturbances responsible for the occurrence of PBS can be induced by chemical agents (exposition to Tigan and Bendectin), mechanical agents (intrauterine edema), gene disturbances (described occurrence of PBS in a Nigerian family), and cases of PBS associated with chromosomal anomalies. The condition similar to PBS has been induced experimentally in animals by gene mutation (Danforth's short-tailed rats). If it is accepted that PBS is in a certain number of cases hereditary, it can be presumed that, according to the Nigerian authors, X related recessive transfer is involved here. As males suffering from PBS are sterile, they cannot transfer pathological genes, that is to say the disease itself. The only theoretical possibility for a female child whose karyotype is 46, XX, to be affected by PBS, would be when it inherits one affected X chromosome from its mother, while the second X chromosome has a mutation de novo. This could be an explanation for an extremely rare occurrence of PBS in female persons. The other explanation, according to McKusick, is that PBS can be also autosomally dominantly inherited (de novo mutation). The incidence of PBS in the female population is probably somewhat increased by "non-genic" etiological factors (chemical and mechanical agents). It is very difficult to say how strong is the influence of a certain factor on the occurrence of PBS. Therefore, it could be concluded that the etiology of PBS is heterogeneous, chromosomal, genic, and multifactorial, but regardless of the factor, it is always the primary field that is affected (in this case the ability of inductive interaction of the mesenchyme) leading to all other disturbances. Everything mentioned so far indicates that according to valid criteria, PBS can be regarded as a malformation, that is, a primary developmental disturbance.(ABSTRACT TRUNCATED AT 400 WORDS)